Microphones used in automobiles are known in the art and may be placed in various locations throughout the vehicle in order to provide the driver with the ability to verbally control functionality of telematics, mobile telephone and other electronic devices within the vehicle. Often, these microphones are placed in the vehicle's rear view mirror so as provide improved performance and save space in the vehicle's instrument console.
Prior art automotive microphones have typically used a directional transducer with the peak polar response pointed directly at the driver or alternatively pointed at a location that is substantially down the center of the vehicle's passenger compartment or cabin. While this technique might help to maximize voice amplitude levels, it does not always maximize the signal-to-noise ratio (SNR) at the microphone. Those skilled in the art will recognize that the interior acoustic environment in an automobile is highly reverberant. This results in standing acoustical wave patterns that give rise to non-uniform sound pressure distributions at the microphone location. While the optimum SNR microphone aim angle is vehicle specific, in most cases the desired aim point of a single microphone or microphone system may be at some other location within the vehicle.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.